The purpose of this research study is to examine sympathetic nervous system activity in older depressed patients before and after completing electroconvulsive therapy. We believe that depressed patients will have evidence of increased sympathetic nervous system activity (as measured by chemical messengers, pulse, and blood pressure) and may not respond to stress as a person without depression would. We further believe that successful treatment with electroconvulsive therapy or medications will cause these measures to be similar to the subjects without depression. Those depressed patients whose sympathetic nervous system activity normalizes may be less likely to have their depression quickly return after treatment. Non-depressed individuals will be studied to obtain control values for the biochemical measures.